More on "Krugman's symmetry proof": it's not whether one gets the answer right or wrong but how one reasons that counts 
Wednesday, April 9, 2014 at 9:19AM
Dan Kahan

Okay, I've finally caught my breath after laughing myself into state of hyperventilation as a result of reading Krugman's latest proof (this is actually a replication of an earlier empirical study on his part) that ideologically motivated reasoning is in fact perfectly symmetric with respect to right-left ideology.

Rather than just guffawing appreciatively, it's worth taking a moment to call attention to just how exquisitely self-refuting his "reasoning" is!

There's the great line, of course, about how his "lived experience" (see? I told you, he's doing empirical work!) confirms that motivated cognition "is not, in fact, symmetric between liberals and conservatives."

But what comes next is an even more subtle -- and thus an even more spectacular! -- illustration of what it looks like when one's reason is deformed by tribalism: 

Yes, liberals are sometimes subject to bouts of wishful thinking. But can anyone point to a liberal equivalent of conservative denial of climate change, or the “unskewing” mania late in the 2012 campaign, or the frantic efforts to deny that Obamacare is in fact covering a lot of previously uninsured Americans?

Uh, no, PK. I mean seriously, no.

The test for motivated cognition is not whether someone gets the "right" answer but how someone assesses evidence.

A person displays ideologically motivated cognition when, instead of weighing evidence based on criteria related to its connection to the truth, he or she credits or dismisses it based on its conformity to his or her ideological predispositions.

Thus, if we want to use public opinion on some issue -- say, climate change -- to assess the symmetry of ideologically motivated reasoning, we can't just say, "hey, liberals are right, so they must be better reasoners."

Rather we must determine whether "liberals" who "believe" in climate change differ from "conservatives" who "don't" in how impartially they weigh evidence supportive of & contrary to their respective positions. 

How might we do that?  

Well, one way would be to conduct an experiment in which we manipulate the ideological motivation people with "liberal" & "conservative" values have to credit or dismiss one and the same piece of valid evidence on climate change.  

If "liberals" (it makes me shudder to participate in the flattening of this term in contemporary political discourse) adjust the weight they give this evidence depending on its ideological congeniality, that would support the inference that they are assessing evidence in a politically motivated fashion.  

If in aggregate, in the real world, they happen to "get the right" answer, then they aren't to be commended for the high quality of their reasoning.  

Rather, they are to be congratulated for being lucky that a position they unreasoningly subscribe to happens to be true.

And vice versa if the "truth" happens (on this issue or any other) to align with the position that "conservatives" unreasoningly affirm regardless of the quality of the evidence they are shown.

That Krugman is too thick to see that one can't infer anything about the quality of partisans' reasoning from the truth or falsity of their beliefs is ... another element of Krugman's proof that ideological reasoning is symmetric across right and left!

For in fact, "the 'other side' is closed-minded" is one of the positions that partisans are unreasoningly committed to. 

One of the beliefs that they don't revise in light of valid evidence but rather use in lieu of truth-related criteria to assess the validity of whatever evidence they see.

This proposition is supported by real, honest-to-god empirical evidence -- of the sort collected precisely because no one's personal "lived experience" is a reliable guide to truth.

That PK is innocent of this evidence is-- another element of his proof that ideological reasoning is symmetric across right and left!

As is his unfamiliarity with studies that use the design I just suggested to test whether "liberals" are forming their positions on climate change and other issues in a manner that is free of the influence of politically motivated reasoning.  Not surprisingly, these studies suggest the answer is no.

But does that mean that all liberals who believe in climate change believe what they do because of ideologically motivated cognition? Or that only someone who is engaged in that particular form of defective reasoning would form that belief?

If you think so, then, despite your likely ideological differences, you & Paul Krugman have something in common: you are both very poor reasoners.

Article originally appeared on cultural cognition project (
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